Enhanced biometric authentication

ABSTRACT

Enhanced biometric authentication is achieved by combining a user&#39;s inherent biometric data with the user&#39;s knowledge of a secret glyph. In one embodiment, a touchpad is provided on which the user may use a finger to indicate a plurality of strokes that form a distinct glyph. Image stabilization may be used to extract a readable fingerprint from the strokes, and the glyph and finger print are matched to a stored profile. The glyph may be one or more alphanumeric characters that represent a password. The user can then enter the password on the touch pad with his finger. If the fingerprint and password both match, the user is authenticated.

BACKGROUND

1. Field of the Disclosure

The present invention relates to the field of biometric authenticationand more particularly to an enhanced device and process for biometricauthentication.

2. Description of the Related Art

A concern with any security system is authentication, i.e., grantingaccess to authorized persons and denying access to unauthorized persons.Successful authentication occurs when a system correctly determines thata user is who he claims to be, usually by the user providing at leastone self-identifying security token. Many electronic systems will use aperson's knowledge, for example of a password, as a security token.Increased security may also be achieved by requiring as a tokensomething in the user's possession, such as a digital certificate. Somesecurity systems will use biometric data, such as fingerprints orretinal scans, as a security token.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of selected elements of an exemplaryembodiment of an enhanced biometric authentication device;

FIG. 2 is a block diagram of selected elements of a fingerprint scannerprovided as one exemplary embodiment of an input sensor;

FIG. 3 depicts selected elements of an exemplary embodiment of abiometric processing engine;

FIG. 4 depicts selected elements of an exemplary embodiment of amechanics processing engine;

FIG. 5 depicts selected elements of an exemplary embodiment of anauthentication engine;

FIG. 6 is a diagram of a fingerprint touch pad disclosing an exemplarycomposite input sample provided as a security token;

FIG. 7 is a diagram of a fingerprint touchpad providing a secondexemplary security token input sample;

FIG. 8 is a diagram of a plurality of fingerprint touch pads, disclosinga third exemplary security token input sample; and

FIGS. 9A, 9B, and 9C are diagrams of a single fingerprint touch pad usedto enter a string of alphanumeric characters in sequence.

DESCRIPTION OF THE EMBODIMENT(S)

In one aspect, a disclosed method for achieving enhanced biometricauthentication includes combining a user's inherent biometric data withthe user's knowledge of a secret pattern. A touchpad may be provided onwhich the user may use a finger to perform a plurality of strokes thatform a distinct pattern. Image stabilization may be used to extract areadable fingerprint from the strokes. The pattern and finger print arematched to a stored profile. A user may train a device to recognizewritten letters. The user can then enter a password on a touch pad withhis finger. If the fingerprint and password both match, the user isauthenticated.

In the following description, details are set forth by way of example tofacilitate discussion of the disclosed subject matter. It should beapparent to a person of ordinary skill in the field, however, that thedisclosed embodiments are exemplary and not exhaustive of all possibleembodiments. Throughout this disclosure, a hyphenated form of areference numeral refers to a specific instance of an element and theun-hyphenated form of the reference numeral refers to the elementgenerically or collectively. Thus, for example, widget 12-1 refers to aninstance of a widget class, which may be referred to collectively aswidgets 12 and any one of which may be referred to generically as awidget 12.

FIG. 1 is a block diagram disclosing an exemplary embodiment of anenhanced biometric authentication device 100 in operation. In FIG. 1,elements of authentication device 100 are shown in rectangular blockswhile data that is provided to or processed by authentication device 100is shown in oval blocks. In the disclosed embodiment, a composite input120 is provided to an input sensor 110. Composite input 120 includes abiometric component 112 and a mechanical component 114. The biometriccomponent 112 may be one of numerous physiological biometric indicatorsknown in the art, such as finger print, hand print, facial scan, retinalscan, body chemistry, or DNA analysis. To facilitate discussion, theexamples in this specification will use a fingerprint as an example, butpersons of ordinary skill in the art will recognize, in light of thisspecification, that other biometric indicators can be adapted to thedisclosed devices and techniques. Mechanical component 114 may includeany combination of mechanical indicators, such as position, motion,time, direction, velocity, pressure, and acceleration. By way ofnon-limiting example, composite input 120 could include a finger tracinga glyph, wherein the biometric component 112 comprises a finger printand mechanical component 114 comprises the tracing motion; or compositeinput 120 could include a person moving his or her eyes, where thebiometric component 112 comprises a retinal scan and mechanicalcomponent 114 comprises the motion of the eyes. Input sensor 110 isoperable to segregate or otherwise distinguish biometric component 112and mechanical component 114.

Mechanical component 114 is provided to a mechanics processing engine140, which creates a mechanical characterization 142. Similarly,biometric component 112 is provided to a biometric processing engine130, which creates a biometric characterization 132. In someembodiments, a characterization is a reduced profile or other type ofrepresentation of the raw data contained in the composite input 120.Profile reduction may be accomplished, for example, by a heuristic modelor by any of the other numerous methods known in the art for matchingbiometric data.

The characterizations 132, 142 are provided to an authentication engine150, which also receives an authentication template 160. Anauthentication template 160 is a stored characterization profile,containing both a mechanical component 164 and a biometric component162. Authentication template 160 may be generated in advance of theattempted authentication. There may also be a tolerance 152 associatedwith authentication template 160. Tolerance 152 may indicate the degreeof allowable difference between characterizations 132, 142 and thecorresponding components 162, 164.

Authentication engine 150 compares characterizations 132, 142 tocomponents 162, 164 of authentication template 160. If bothcharacterizations match the respective components of authenticationtemplate 160 within tolerance 152, the user is authenticated, and anauthentication 170 is provided. In some cases, feedback 180 may also beprovided to indicate whether or not the user was successfullyauthenticated.

FIG. 2 is a block diagram of selected elements of a fingerprint scanner110-1 provided as an exemplary implementation of an input sensor 110.Persons of skill in the art will recognize that alternative fingerprintscanners, as well as other biometric input sensors, may be suitable forthe same function. In the disclosed embodiment, a touch surface 210provides an interface for receiving composite input 120. A sensor array220 reads the fingerprint using a fingerprint scanning technology,several of which are known in the art. For example, optical, capacitive,and ultrasonic type sensors are all known in the art. A transducer 230digitizes the composite input 120 and provides digital data to apre-processor 240. Pre-processor 240 is powered by power source 250,which also may provide power to transducer 230 as necessary to implementthe fingerprint scanning technology. A clock 270 is also provided toenable pre-processor 240 to handle timing issues related to capturing amechanical component of composite input 120. Pre-processor 240 processesthe digital data to generate mechanical component 114 and biometriccomponent 112. In the depicted embodiment, pre-processor 240 may haveaccess to processor executable instructions that comprise apre-processing algorithm 262. As depicted in FIG. 2, pre-processingalgorithm 262 is stored in a memory 260 that is accessible topre-processor 240.

FIG. 3 is an exemplary embodiment of a biometric processing engine 130.Biometric processing engine 130 receives biometric component 112 frominput sensor 110 (FIG. 1). A biometrics processor 340 is provided tohandle the necessary processing. While shown separately, persons havingskill in the art will recognize that the disclosure describes functionaldistinctions, but that biometrics processor 340 may be a single physicaldevice with some or all of pre-processor 240 (FIG. 2), mechanicsprocessor 440 (FIG. 4), and processor 540 (FIG. 5). Biometrics processor340 is communicatively coupled to memory 360, which also may be a singlephysical device with any or all of memory 260 (FIG. 2), memory 460 (FIG.4), memory 560 (FIG. 5). Memory 360 as shown includes instructions thatprovide a characterization algorithm 362, which provides a method forcharacterizing biometric component 112. Many such algorithms are knownin the art. For example, U.S. Pat. No. 6,963,659 issued to Tumey, et al.on Nov. 8, 2005 discloses a heuristic algorithm for fingerprintmatching.

Because composite input 120 includes a mechanical component 114 (FIG.1), an image stabilizer 342 may be desirable or required to permitbiometric processing engine 130 to extract a usable biometric sample.Image stabilizer 342 may employ a technique such as extracting a singleframe from a high-frequency composite input sample so as to provide asteady-state image of the biometric component, or a reasonableapproximation thereof. Image stabilizer 342 may also provide additionalsharpening or other processing as necessary to clean up residual blur orother artifacts created by mechanical inputs. Persons of skill in theart will recognize that, while image stabilizer 342 is shown as part ofbiometrics processing engine 130, some or all of the functionality couldalso be provided in input sensor 110 as necessary to suit a particularimplementation.

Characterization algorithm 362 creates a biometric characterization 132of biometric component 112 and provides biometric characterization 132as an output. In the case of a fingerprint, for example, the biometriccharacterization 132 generated by characterization algorithm 362 mayinclude data representative of or indicative of the fingerprint. Thedata may be compliant with a standardized format for representingfingerprints.

FIG. 4 is a block diagram disclosing an exemplary embodiment of amechanics processing engine 140. As described above, mechanicsprocessing engine 140 may share some or all of its hardware withbiometrics processing engine 130 and authentication engine 150.Mechanics processing engine 140 receives mechanical component 114 as aninput. Mechanics processing engine 140 as shown includes mechanicsprocessor 440 connected to memory 460, in which is stored instructionsthat provide a mechanical characterization algorithm 462.Characterization algorithm 462 may provide any one of numerous possiblealgorithms, depending on the specific implementation. For example, insome embodiments, mechanical component 114 may describe an arbitraryglyph designated by the user (see, for example, FIG. 6). As used in thisspecification, a glyph is any symbolic figure or character that conveysinformation non-verbally. In that case, mechanical component 114 maycontain such information as the number of strokes, the order of thestrokes, the location of the strokes on the touch pad 110-1, theorientation or direction of the strokes. This information may beconveyed, for example, by indicating the beginning and ending locationof each stroke. In some embodiments, touch pad 110-1 may be divided intosectors, as shown in FIG. 6, and location information may includeinformation such as the sector in which the stroke was begun, sectorsthe stroke traversed in which order, and the sector in which the strokeended. Mechanics processor 440 invokes characterization algorithm 462 togenerate a mechanical characterization 142, which is an output ofmechanics processing engine 140.

FIG. 5 is a block diagram of an exemplary embodiment of anauthentication engine 150, which as described above may share some orall of its hardware with input sensor 110, mechanics processing engine140, and/or biometric processing engine 130. Authentication engine 150receives biometric characterization 132 and mechanical characterization142. An authentication template 160 may be stored in non-volatilestorage and also provided to authentication engine 150. Anauthentication processor 540 is connected to a memory 560. Memory 560includes instructions that provide a glyph matching algorithm 530. Glyphmatching algorithm 530 compares biometric characterization 132 andmechanical characterization 142 to authentication template 160 whichincludes a biometric component 162 and a mechanical component 164. Forglyph matching algorithm 530 to indicate a good match, both biometriccharacterization 132 and mechanical characterization 142 must match datain authentication template 160. If glyph matching algorithm 530indicates a match, then authentication processor 540 generatesauthentication 170.

FIG. 6 is a diagram of a fingerprint touch pad 110 indicating anexemplary composite input 120 provided as a security token. In thisexample, the composite input 120 includes a three-stroke glyph drawn bythe user's index finger. The first stroke 611 is drawn by starting insector 1 and, in a substantially straight downward motion, traversingsector 4 and ending in sector 7. The second stroke 612 is drawn startingin sector 2, traversing sector 4 in a downward and left diagonal motion,and ending in sector 6. The third stroke 613 is made by starting insector 3, traversing sector 4 in a rightward horizontal motion, andending in sector 5. In this example, the foregoing data are stored in anauthentication template 160 along with a sample of the user'sfingerprint during a template creation process or procedure. When a userlater attempts to authenticate, biometric processing engine 130 willtake one or more samples of the user's fingerprint from touch pad 110and authentication engine 150 will determine whether there is a matchwith the fingerprint data in authentication template 160. Mechanicsprocessing engine 140 may provide data about the order and shape of thestrokes, including information such as the starting sector, endingsector, sectors traversed, and general direction. Authentication engine150 may determine whether these data match mechanical data in theauthentication template 160. If both the fingerprint and the mechanicaldata match biometric component 162 and mechanical component 164 in theauthentication template 160, the user may be authenticated.

FIG. 7 illustrates a second example of providing authentication via atouch pad 110. In FIG. 7, the user traces a glyph that lookssubstantially like a letter “Z.” Authentication template 160 could storestroke data such as in FIG. 6, in which case the order and shape of thestrokes may need to be matched to provide authentication. But as analternative, mechanics processing engine 140 characterization algorithm462 may include a handwriting recognition component that recognizesalphanumeric characters and, optionally, user specific characteristicsof one or more alphanumeric characters. In that case, mechanicsprocessing engine 140 may only provide, for example, the ASCII code forthe letter “Z,” and possibly additional data representing user specificcharacteristics of the input. Authentication template 160 would likewisecontain only the ASCII code for the letter “Z” in its mechanical dataand possibly a user specific data if needed. This method may simplifyauthentication for the user. Rather than having to remember the specificstrokes, including starting and ending sectors, the user would only needto remember a letter. On the other hand, this method may be less securethan the method of FIG. 6, as alphanumeric characters comprise arelatively small, bounded set.

In one embodiment, a user trains biometric authentication device 100with sample inputs of a plurality of glyphs. Authentication may thencomprise a step of presenting the user with one or morerandomly-selected glyphs and receiving a composite input 120corresponding to each glyph. Advantageously, this may pose difficultiesfor a non-authentic user, because he cannot learn a password as part ofcomposite input 120.

FIG. 8 is a diagram of a plurality of fingerprint touch pads 110, whichmay provide additional security over the method of FIG. 7. In thisexample, three touch pads 110-1, 110-2, and 110-3 are provided. The usermay choose a random three-character alphanumeric string such as “CTR”for authentication. In this case, “C” input 120-1 is entered on firsttouch pad 110-1, “T” input 120-2 is entered on second touch pad 120-2,and “R” input 120-3 is entered on third touch pad 110-3. The user isauthenticated only if those three letters are entered on those pads inthat order. To further enhance security, users may be required to usethe pads in a non-sequential order. For example, instead of entering theletters in the order “C” “T” “R,” the user may enter the letters on thetouch pads as disclosed, but in the order “T” “C” “R.” This provides theadditional security measure of requiring the user to know not only theletters to be entered on each pad, but the order in which the lettersare to be entered.

FIGS. 9A, 9B, and 9C are diagrams of a single fingerprint touch pad 110used to enter a string of alphanumeric characters. In this case, theuser chooses the pass phrase “C” “T” “R” as before. Rather than enteringthe letters on three separate touch pads, the user enters the letterssequentially on a single touch pad 110. This method provides the addedbenefit of allowing a pass phrase of arbitrary length and reduceshardware costs by employing just a single touchpad 110. For example,rather than the short phrase “CTR,” the user may choose as his passphrase a longer random string, including non-alphanumeric characters,such as “PTu7%5x”. This method provides the ability to use the same typeof pass phrase that is commonly used in the art, but with the addedsecurity measure that the pass phrase must be entered with a fingermatching the fingerprint stored in authentication template 160. Anotheradvantage to the use of pass phrases is that hashing algorithms may beemployed so that authentication template 160 need not store mechanicaldata in a format that would be accessible if authentication template 160itself were compromised. For example, if authentication template 160contained the string “PTu7%5x,” a malicious user who gains access toauthentication template 160 would learn the pass phrase portion ofauthentication template 160. Not only would this weaken the security ofenhanced biometric authentication device 100, but it may also weakensecurity for other systems, as many users re-use their passwords onmultiple systems. But if authentication template 160 stores only a hashof the pass phrase, then a malicious user would not learn any usefuldata, even if he gained access to authentication template 160. Anotherpotential solution is to store mechanical component 164 of template 160in a machine-usable form, and then to use biometric characterization 132as an encryption key to encrypt mechanical component 164. Thus,mechanical component 164 can only be decrypted for use with a correctbiometric characterization.

In one exemplary application of the method of FIG. 9, a laptop ordesktop computer could include a mouse pad that also includesfingerprint-sensing technology. When the user logs in, he will “write”his pass phrase, one character at a time, on the mouse pad. The userwill be authenticated only if both the pass phrase and the user'sfingerprint match, as determined by a finger print matching algorithmand a hash function performed on the pass phrase.

To the maximum extent allowed by law, the scope of the presentdisclosure is to be determined by the broadest permissibleinterpretation of the following claims and their equivalents, and shallnot be restricted or limited to the specific embodiments described inthe foregoing detailed description.

1. An enhanced biometric authentication device comprising: an inputsensor configured to receive composite inputs from a plurality of touchpads, each composite input comprising a biometric component and amechanical component; a biometric processing engine communicativelycoupled to the input sensor and configured to receive the biometriccomponents and generate a biometric characterization from the biometriccomponents; a mechanics processing engine communicatively coupled to theinput sensor and configured to receive the mechanical components andgenerate a mechanical characterization from the mechanical components;and an authentication engine, the authentication engine configured to:receive the biometric characterization from the biometric processingengine; receive the mechanical characterization from the biometricprocessing engine; compare the biometric characterization and themechanical characterization to an authentication template to determinewhether each of the composite inputs is indicative of a correspondingglyph in the authentication template and whether each of the compositeinputs was entered on a correct touch pad; and authenticate a user basedon the comparison.
 2. The enhanced biometric authentication device ofclaim 1 wherein: at least one of the touch pads is configured toidentify fingerprints; and the biometric component of the compositeinputs includes a fingerprint.
 3. The enhanced biometric authenticationdevice of claim 1: further comprising a second input sensor configuredto receive a second composite input; and wherein: the mechanicsprocessing engine is further configured to determine the order in whichthe user inputs are received; the authentication template comprises datathat specify an order of the composite inputs; and the authenticationengine is further configured to compare the order in which the compositeinputs are received to the order specified in the authenticationtemplate.
 4. The enhanced biometric authentication device of claim 1wherein the mechanical component of the composite input describes aglyph.
 5. The enhanced biometric authentication device of claim 4wherein the glyph represents an alphanumeric character.
 6. The enhancedbiometric authentication device of claim 4 wherein: the mechanicalcomponents of the composite inputs indicate glyphs representingalphanumeric characters; the authentication template contains a stringof alphanumeric characters; and the authentication engine is furtherconfigured to compare the string of alphanumeric characters with themechanical components of the inputs to determine that the mechanicalcomponents match the string of alphanumeric characters.
 7. The enhancedbiometric authentication device of claim 1 wherein the authenticationtemplate includes a biometric component and a mechanical component. 8.The enhanced biometric authentication device of claim 7 wherein: eachtouch pad comprises a surface divided into sectors; the authenticationtemplate contains data describing traversal of sectors in creating astored glyph; and the authentication engine is further configured tocompare the mechanical component of the composite input sample to thedata describing traversal of sectors in the authentication template. 9.The enhanced biometric authentication device of claim 7 wherein: theglyph comprises a plurality of strokes; the authentication templatecontains a mechanical component describing a plurality of strokes; andthe authentication engine is further configured to compare the strokesto the mechanical component.
 10. The enhanced biometric authenticationdevice of claim 9 wherein: the data describing a plurality of strokesincludes information describing a stroke sequence, a stroke placement,and stroke orientation or direction; and the authentication engine isfurther configured to compare the sequence of the plurality of strokeswith the data in the mechanical component of the authenticationtemplate.
 11. The enhanced biometric authentication device of claim 1wherein the biometric processing engine includes an image stabilizerconfigured to provide a steady-state representation of the biometriccomponent of the composite input sample.
 12. A method of authenticatinga user, the method comprising the steps of: receiving a composite inputfrom the user; processing the input to identify a biometric componentand a mechanical component; processing the biometric component to createa biometric characterization of the biometric component; processing themechanical component to create a mechanical characterization of themechanical component; and determining that the user is authentic bycomparing the biometric characterization and mechanical characterizationto a previously stored authentication template including a biometriccomponent and a mechanical component; wherein receiving a compositeinput sample from the user comprises receiving inputs on a plurality oftouch pads, the mechanical component of each input describing a glyph;the characterization profile associates each input glyph with one of theplurality of touch pads; and determining that the user is authenticfurther comprises determining that: each glyph matches a glyph in theauthentication template; each glyph was entered on the correct touchpad; and the glyphs were entered in the correct order.
 13. The method ofclaim 12 wherein: receiving a composite input sample from the usercomprises receiving a plurality of inputs on a single touch pad, themechanical component of each input comprising a glyph representing analphanumeric character; the authentication template is indicative of anordered series of alphanumeric characters; and determining that the useris authentic comprises comparing each glyph with each alphanumericcharacter of the ordered series and determining that each glyph matchesthe corresponding alphanumeric character.
 14. A method of providingenhanced security for a system, the method comprising the steps of:creating an authentication template for a known user by: receiving froma first touch pad a first composite input from the known user, the firstcomposite input sample comprising a biometric component and a mechanicalcomponent; characterizing the biometric component of the first compositeinput sample; characterizing the mechanical component of the firstcomposite input sample; storing the characterized biometric componentand mechanical component in an authentication template; authenticatingan unknown user by: receiving from a second touch pad a second compositeinput sample from the unknown user, the second composite input samplecomprising a biometric component and a mechanical component;characterizing the biometric component; characterizing the mechanicalcomponent; comparing the characterized biometric component andmechanical component to the authentication template; and associating theunknown user with the known user if the characterized biometriccomponent and characterized mechanical component match respectivecharacterized biometric and mechanical components of the authenticationtemplate within a tolerance.
 15. The method of claim 14 wherein thebiometric component of the first composite input sample and secondcomposite input sample is a fingerprint.
 16. The method of claim 14wherein the mechanical component of the first composite input sample andthe second composite input sample comprises an ordered sequence ofstrokes.
 17. The method of claim 14 wherein the mechanical component ofthe first composite input sample and the second composite input samplecomprises a string of glyphs, the glyphs comprising an ordered sequenceof strokes, and at least some of the glyphs representing alphanumericcharacters.
 18. The method of claim 12 wherein: the mechanicalcomponents of each composite input comprises a plurality of strokes,each stroke having a characteristic shape; and determining that the useris authentic further comprises determining that characteristic shapes ofthe strokes match the authentication template.
 19. The method of claim18 wherein: determining that the user is authentic further comprisesdetermining that the strokes were entered in a sequence that matches asequence in the mechanical component of the authentication template.